Tetracyanonichelate (II) ion

Tetraammine zinc (II) ion

Hexaammine chromium (III) ion

Diammine silver (I) ion

Both belong to d block

Both belong to the same group of periodic table

Both have similar radii

Both have same number of electrons

In the lower part, called zone of fusion temperature (1773 K), coke burns to CO₂ producing 97000 calories of heat

In the middle part, limestone decomposes to give CO₂ and lime which acts as a reducing agent

In the middle part, called zone of heat absorption (1073 − 1273 K), CO₂ is reduced to CO

At the top is the zone of reduction (673 − 973 K). Here, iron oxide is reduced to spongy iron by CO

Ferric nitrate

Ferric nitrate and NO₂

Ferrous nitrate and ammonium nitrate

Ferrous nitrate and nitric oxide

Copper

Silver

Nickel

Iron